Esophagitis (or oesophagitis) is an inflammation of the esophagus. The prefix esophag/o refers to the esophagus and the suffix -itis means inflammation. The esophagus is part of the digestive system, specifically the gastrointestinal tract. It is a muscular tube where food passes through from the mouth to the stomach. Esophagitis is a disease that can be painful and can make swallowing difficult. However, esophagitis can be asymptomatic. Infection, irritation, and/or inflammation of the lining of the esophagus can cause esophagitis. The most common cause of esophagitis is gastroesophageal reflux disease (GERD). There additionally are several types of esophagitis, some not correlated with GERD.